The completion of the first round and the start of the second round at the Western and Southern Open saw the tournament take on a whole new look after the top two seeds were both knocked out.
Top seed Karolina Pliskova was upset by Veronika Kudermetova in straight sets while second seed Sofia Kenin also went down in two to Frenchwoman Alize Cornet.
Those were the only two second round matches to take place while 13 first round contests were played as the tournament moves into high gear.
Kudermetova, Cornet conquer top two seeds
The Russian authored a 7-5, 6-4 upset over Pliskova to reach the third round. The Czech jumped out to a 4-1 first set lead only to see Kudermetova fight back and go up a break when the top seed saw a backhand clip the tape and land on her side.
She served out the first set with ease and the world number 41 grabbed the only break of the second set in the ninth game when Pliskova sent a forehand long. Tasked with serving out the match, she did so, wrapping up the win with another error off of the racket of the top seed.
"I tried not to think about the score", she said afterwards. "I tried to fight, tried to continue (to) play like every ball, tried to enjoy like I play in the big stadium against the first seeded. It was (a) nice feeling and I tried to just fight and enjoy it. I think right now I play really well.
"I have yesterday the longest match, today I have a long match. For me it's a good opportunity to play, like, right now with the good players. I know she's a really good player. I needed to just keep working every point. I had a good chance because I played yesterday. She played [just] her first match."
Cornet raced out to a 5-0 lead against the reigning Australian Open champion and closed out the opening set two games later when Kenin flew a forehand long after just half an hour of play. The Frenchwoman kept up her high level of play, grabbing an early break in the second set.
She extended the lead to 5-2 before the second seed made a stunning comeback, saving match points in the process to force a tiebreaker. Cornet jumped out to a 4-1 lead only to see Kenin reel off five points in a row before the Frenchwoman rallied back, sealing the upset when Kenin sailed a backhand just wide.
"I'm a fighter", she assessed after the match. "I'm always fighting, so that's nothing new, but tonight was tough because I was 6-1, 5-2 up with two match points. Somehow, I let it go a little bit, and I got really tight, so I never thought I could win the set the way I did.
"It was a really tight second set, and in the tie-break, oh my God, I was just praying for the best on every single shot."
Vondrousova, Stephens also fall
10th seed Marketa Vondrousova joined Pliskova and Kenin on the sidelines, falling to Laura Siegemund 6-3, 6-7 (3), 6-4. The qualifier will face another qualifier in the second round in Vera Zvonareva, who knocked off Magda Linette 1-6, 6-3, 6-1.
Sloane Stephens' slump also continued as she fell to Caroline Garcia 6-3, 7-6 (4). The American built a 3-1 lead only to watch the Frenchwoman run off six straight games to build a set and a break lead.
Stephens roared back and look poised to force a third set as she built a 5-3 advantage. Garcia rallied to force a tiebreaker and won six of the final seven points to post her third win in four meetings against the former US Open champion.
"I was expecting a tough draw", she said. "Because when you see the draw, the girls in qualifying, it's kind of amazing. You're like 'Okay, if you're not seeded I'm going to play a good girl. Even if she is not seeded, there's only going to be good girls.
"I felt pretty good. I'm very happy the way I was playing and especially moving on court. I think probably mentally you have to be focused on every single point. It's something I have been struggling in the past months before everything. I know it's something I can improve on and it can help me a lot to get some wins."
Kontaveit, Mertens, Teichmann among other winners
Seeded players that fared better were 12th seed Anett Kontaveit, who blew past Daria Kasatkina 6-3, 6-1 to set up a second round meeting with Lexington finalist Jil Teichmann, a 6-3, 6-3 victor over Danielle Collins as well as 14th seed Elise Mertens, who won the first ten games in a 6-0, 6-2 rout of Rebecca Peterson.
Catherine Bellis edged past qualifier Oceane Dodin 6-2, 3-6, 7-6 (1) to set up a meeting with fifth seed Aryna Sabalenka. Marie Bouzkova knocked off qualifier Anna Kalinskaya 6-1, 7-5 and will play sixth seed Petra Kvitova next. Arantxa Rus blew away Alison Van Uytvanck 6-2, 6-2 and faces a big challenge in third seed Serena Williams in round two.
Qualifiers Kirsten Flipkens and Jessica Pegula moved on as the Belgian defeated Katerina Siniakova 6-3, 6-3 to book a matchup with eighth seed Johanna Konta while the American slipped past Lexington champion Jennifer Brady 7-6 (5), 6-4. Yulia Putintseva was a 6-4, 6-3 winner over Shuai Zhang while Christina McHale scored an impressive 6-2, 6-4 victory over Iga Swiatek.